Glossary
What is overlap rate in auction insights?
Melvin Salas1 min readVerified 9 October 2026
Short answer
Overlap rate is a column in the Google Ads auction insights report. Google defines it as how often another advertiser's ad received an impression when your ad also received an impression. A row showing 60% means that in 6 out of every 10 times your ad showed, an ad from that advertiser showed as well.
The count starts from your own impressions. Our reading: an auction where the rival's ad showed and yours did not is not in this number at all, so overlap rate says how often you met that advertiser when you were there, not how often they were there.
Google lists overlap rate among the six statistics in the auction insights report for Search campaigns and the three for Shopping campaigns. The report doesn't show insights when impression share is less than 10%, and Google notes that search partners won't be included in the auction insights data.
Read it with position above rate, which Google says is how often the other advertiser's ad was shown in a higher position than yours was, when both of your ads were shown at the same time. Our reading: overlap rate says how often the two ads met, and position above rate says who sat higher when they did.
Read it with outranking share as well. Google's outranking share includes how often your ad showed when the rival's didn't. Our reading: when overlap rate falls, more of your impressions came with no ad from that rival, and each of those auctions can lift your outranking share without your ad having ranked above theirs.
Reading these columns is daily work for us
Riibon watches every campaign daily and holds a baseline for each metric, so a move in impression share or Quality Score is judged against what is normal for that account, not against a rule of thumb, before anyone acts on it.
Ask the Riibon app whether your campaigns are losing to budget or to rank. It is free, with no time limit and no card. Or book a call and we run it for you.